A New 1D Cd(Ⅱ) Coordination Polymer Constructed by 2,2'-H_2biimidazole:[Cd(H_2biim)_2(SO_4)]_n·3nH_2O

A new 1D Cd(II) coordination polymer, [Cd(H2biim)2(SO4)]n·3n H2O(1, H2 biim = 2,2'-H2biimidazole), has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 6.8405(14), b = 17.792(4), c = 14.987(3) A, β = 92.68(3), V = 1822.1(6) A3, Z = 4, C12H18 Cd N8O7S, Mr = 530.80, Dc = 1.935 g/cm3, F(000) = 1064, μ(Mo Ka) = 1.371 mm-1, R = 0.0280 and w R = 0.0617. In 1, adjacent Cd(II) atoms are bridged by sulfate anions in bidentate modes to yield a 1D chain. H2 biim ligands are located on both sides of the chain in chelating bidentate modes. Further, the H2 biim ligands from neighboring chains are paired through π-π interactions to generate a supramolecular layer, which is stabilized by the complicated N–H···O and O–H···O hydrogen bonds. In addition, thermal behavior and luminescent property of 1 have been investigated.     

烯丙基自由基(·C3H5)与氧气(O2)反应机理的理论计算

用量子化学计算方法对CH3CH=·CH与O2气的反应机理进行了理论研究, 在B3LYP/6-311G(d,p) 水平下优化稳定分子结构和寻找过渡态, 并在此构型的基础上, 采用CCSD(T)/6-311G(d,p)方法得到各驻点的高级单点能量. 找到主要路径R(CH3CH=·CH+O2)→m1(trans-CH3CH=CHOO)→m2(形成COO三元环)→m3(C—C键断裂,同时生成CH3CH—O—CHO)→P2(C—O键断裂生成CH3CHO+CHO); 并与C2H3等共轭体系进行了对比.     

大功率BUCK变换器电压电流尖峰的分析及抑制措施

在大功率Buck变换器中电路工作于高频开关状态,由于实际线路的寄生参数和器件的非理想特性的影响,开关器件两端会出现过高的电压和电流尖峰,严重地降低了电路的可靠性。本文详细分析了两种尖峰产生的原因和危害,有针对性地提出了几种RCL缓冲电路,并给出了电路各参数的分析和设计方法。仿真和使用结果证明了该缓冲电路具有良好的软开关效果,对于主开关管的电压尖峰和电流尖峰具有较强的抑制作用。     

Synthesis and Crystal Structure of a New Two-dimensional Manganese Coordination Polymer： [Mn（L）（1,4-bdc）]

A new coordination polymer,[Mn(L)(1,4-bdc)] (L=11-fluoro-dipyrido[3,2-a:2,3-c]phenazine,1,4-bdc=benzene-1,4-dicarboxylate),has been synthesized through the hydrothermal method and characterized by elemental analysis,IR and single-crystal X-ray diffraction.It crystalli-zes in triclinic,space group P1 with a=9.7544(9),b=10.8254(10),c=11.5288(10),α=114.1300(10),β=96.6110(10),γ=105.0390(10)°,V=1038.62(16)3,Z=2,C 26 H 13 FMnN 4 O 4,M r=519.34,D c=1.661 g/cm 3,F(000)=526,μ(MoKa)=0.691 mm-1,R=0.0405 and wR=0.0977.The 1,4-bdc dianions link the neighboring Mn(II) atoms to yield a two-dimensional layer structure.The L ligands are attached on both sides of the layer.The π-π interactions between the L ligands of neighboring layers result in a three-dimensional supramolecular architecture.     

柔性二羧酸和双咪唑配体共同构筑的二重穿插的镍(Ⅱ)配位聚合物

本文报道了1个二重穿插的配位聚合物[Ni2(1,2-bix)2(oba)2(H2O)2],并对该化合物进行了元素分析、红外和单晶X-射线表征(1,2-bix=1,2-(二亚甲基苯)二咪唑配体,oba=4,4′-氧联苯二甲酸阴离子)。该化合物属于单斜晶系,空间群P21/n,晶胞参数a=1.475 3(5)nm,b=1.684 1(4)nm,c=2.135 6(5)nm,β=102.864(3)°,V=5.173(2)nm3,Z=4,R=0.040 5,wR=0.101 0。在该化合物中,oba和1,2-bix连接着Ni(Ⅱ)原子形成二维(4,4)网络结构。2个相邻的(4,4)网络相互穿插形成了二重穿插的二维层状结构。O-H…O氢键进一步地稳定了此层状结构。     

枝状文石型碳酸钙的仿生合成及在PVC中的应用

利用生物矿化原理,以聚丙烯酸(PAA)为有机基质,采用碳化法合成了具有枝状形貌的文石型碳酸钙粒子.通过场发射扫描电镜(FESEM)、X射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)等检测手段研究了产物的结构和形貌,并初步探讨了粒子的生长机理.结果表明,在文石型碳酸钙粒子的合成中,有机基质和反应温度是非常重要的参数.同时将该产品填充于聚氯乙烯(PVC)中,测定了PVC塑料的力学性能和加工性能.